1. Field of the Invention
The present invention relates to a firearm, especially an automatic pistol, with at least a barrel and a slide which move relative to the rest of the firearm and to each other. The barrel extends through an alignment channel in the slide.
2. Description of the Related Art
The Colt-Browning is one example of such a system. Discharge of the weapon is followed by relative motions on the part of various subassemblies. The barrel and slide in particular carry out a joint longitudinal motion. The barrel also tilts relative to the slide. To allow these motions and especially the tilt of the barrel requires considerable play between the outer surface of the barrel and the inner surface of the alignment channel. The same degree of play is needed to accommodate heat expansion on the part of the barrel. The expansion of the barrel is more extensive when the weapon is discharged cold than the expansion of the alignment channel is when the channel is allowed to gradually warm up to the temperature of the barrel. It is, however, essential to ensure that the barrel can tilt in the channel in spite of the heat expansion. The play is also necessary, finally, to prevent contaminants from jamming the weapon.
The weapon's accuracy is of course considerably decreased by the play. More precisely, the scatter pattern of impacts on a particular target is enlarged. This enlargement is even more evident for the first shot subsequent to rechambering, at least when the cartridges are chambered both manually and automatically. How the weapon closes depends on how rapidly the chambering occurs. The first shot is usually too low.
These drawbacks have allegedly been eliminated in a US military pistol specially modified for sports purposes (Model 1911 A1). The barrel-alignment channel is wider, and a new type of barrel is employed, with a barrel-centering protuberance around its outer surface. The protuberance is inside the channel and rests relatively snug against its inner surface before the weapon is discharged. The diameter of the protuberance must precisely equal that of the channel. It is accordingly impossible to replace the barrel rapidly and easily, given the conventional outside-diameter tolerances. The expansion of the barrel and hence of the protuberance that occurs when the weapon is discharged also makes it necessary to prevent jamming by lubricating the weapon and to avoid firing highly charged cartridges. Still another unsolved problem that occurs in conjunction with this embodiment, finally, is connected with contamination. Even low levels will cause the protuberance to wear down rapidly. The aforesaid approach has accordingly almost never been employed until now for military purposes, by ordnance for example. It is and always has been on the other hand particularly for military purposes that firing precision is most necessary. Although the problem has been recognized for more than 80 years, no solution has as yet been discovered.